The statements in this section merely provide background information related to the present disclosure and may not constitute prior art.
Engines such as diesel engines produce particulate matter (PM) that is filtered from exhaust gas by a PM filter. The PM filter is disposed in an exhaust system of the engine. The PM filter reduces emission of PM that is generated during combustion.
Over time, the PM filter becomes full. During regeneration, the PM may be burned within the PM filter. Regeneration may involve heating the PM filter to a combustion temperature of the PM. There are various ways to perform regeneration including modifying engine management, using a fuel burner, using a catalytic oxidizer to increase the exhaust temperature with after injection of fuel, using resistive heating coils, and/or using microwave energy. The resistive heating coils are typically arranged in contact with the PM filter to allow heating by both conduction and convection.
PM reduction systems that use fuel tend to decrease fuel economy. For example, many fuel-based PM reduction systems decrease fuel economy by 5%. Electrically heated PM reduction systems reduce fuel economy by a negligible amount, but are operation limited based on exhaust flow. As exhaust flow increases, for example, above a particular flow rate (kg/s), the facilitation and ability to initiate regeneration by an electrically heated element decreases.